Rotary kiln



Oct. 11, 1938.

l-l, VANDERWERP v .2,132,709

ROTARY KILN Filed Nov. 50, 1934 6 Sheets-Shea?l l www Cet. 11, 1938. HVANDERWERP' 2,132,709

' i ROTARY KILN Filed Nov. so, 1?:54 e sheets-sheet 2 we( ,ff

fel/f Oct. 1-1, 1938. H. vANDERwERP l 2,132,709

RoTARY KILN l l Filed Nov. 30, 1954 6 Sheets-Sheet 3 jizz/672237' Oct.1l, 1938.

H. VANDERWERP ROTARY KILN Filed Nov. 50, 1934 G'SheetS-Sheel 4 O'ct. 11,1938. H. vANDERwERjP ROTARY KILN Filed Nov. 30, 1934 6 Sheets-Shea?l 5.L. I I L l l l l 01:1, 11, 1938. VANDERWERP- 2,132,709

ROTARY KILN e sheets-sheet e' Filed Nov. 50, 1934 Patented Oct. 1 1,1938 UNITED STATE rusrErrrA OFFICE 5 Claims.

This invention relates to rotary kilns of the type commonly used forproducing cement clinker, and relates particularly to combination heatrecuperators and clinker coolers for such kilns, designed and adaptedfor pre-heating air delivered to the kiln for combustion purposes and atthe same time, cooling the clinker discharged from the kiln.

As regards its general features and excepting as hereinafter may beparticularly described and pointed out, the combination recuperator andcooler of the present application is of the same general type as thatwhich forms the subject-matter ofmy pending application, filed October3, 1932, and numbered seriallyl 635,991, to which reference is here madeas to features herein shown, but not fully described.l

In 'addition to the objects sought to be attained by the apparatus of mysaid prior application, No. 635,991, objects of the present inventionare to provide an improved construction and arrangement of themeans forcontrolling the volume of air supplied to the kiln for supportingcombustion of the fuel charge, for regulating the temperatures in thekiln, for cooling the clinker discharged from the kiln, whereby a volumeof air may be supplied to the kiln in excess of the volume supplied byany other apparatus for the purpose, of which I have any knowledge, andto prevent cracking and breaking of ,metallic portions of therecuperator and cooler exposed within the kiln by contractionandexpansion due to the high temperatures and Vexcessive variations intemperatures to whichthey will be subjected in operation.

To attain the objects thereof, a combination recuperator and coolerembodying my invention and improvements, comprises the various features,combinations of features and details of construction hereinafterdescribed and claimed.

In the accompanying drawings, in which the invention is, fullyillustrated,

Figure 1 is a top plan view of. the material discharge'end of a rotarykiln to which a combination recuperator and cooler embodying myinvention and improvements is applied.

Figure 2 is a side elevation of the structure shown in Fig. l.

Figure 3 is a sectional elevation substantially on the line 3-3 of Fig.4.

Figure 4 is a sectional elevation substantially on the line 4-4 ofFig. 1. A

Figure 5 is a sectional end view substantially on the line 5-5 of Fig.2,"the supporting standards for the wind-box being shown in elevation.

` Figure 6 is an enlarged, fragmentary, sectional side view on the line6--6 of Fig. 1. Figure '7 is a detached view of the Wind-box from theleft side of Fig. 8.

Figure 8 is a sectional view of the wind-box substantially on the line 88 of Fig. 7, broken away in part.

Figure 9 is a detached face view of the blastring for supplying air fromthe wind-box to the manifolds.

Figure 10 is an enlarged, sectional elevation, substantially on the linelll- 10, Fig. 5.

Figure 11 is a detached, perspective view of a tuyre block forming partof the means for supplying air to the kiln.

Figure 12 is a sectional view of said tuyre block on the line i2-l2 ofFig. 11. I

Figure 13'is an enlarged, detached plan view of an extreme end,flue-forming member.

Figure 14 is a side view of said member, partly in section.

Figure 15 is a view, similar to Fig. 14, termediate flue-forming member.

Figure 16 is a sectional view of the line of either Fig..14 or 15.

Figure 17 is a fragmentary detail sectional View on the line I'l--ll ofFig. 6, showing the means for mounting the blast-ring on the nipplessecured to the manifolds supported on the shell of the kiln; and

Figures 18 to 22, inclusive, are fragmentary views illustratingstructural details of the Windbox.

Describing the invention with reference to the drawings, in which forpurposes of clear and definite illustration, I have shown my inventionand improvements applied to a well known type of of an inlS-l kiln forproducing cement clinker, designated as a whole A, and which comprises ausual rotary shell l, having a lining 2 of suitable refractory material,which for reasons presently apparent..

` ator for pre-heating air supplied to the kiln for combustion purposesand for cooling clinker about to be discharged from the kiln,circumferentially spaced, longitudinal air ues 6 are provided on theinner surface of the shell I of the kiln A, between the lower end of thelining 2 and the discharge end of the kiln, and which form a seriesextending entirely around the kiln. For purposes of convenientreference, said combination recuperator and cooler is designated as awhole B. i

In what Inow consider preferable construction, see particularly Figs. 3to 6, said air ues 6 are formed by hollow castings designated as a wholeb, preferably made of suitable heat re-` j ends of all flue castings areopen, as shown, see

Figs. 13 to 16.

Also, to save metal and to reduce the weight thereof, openings 9 areformed in the lateral sides of said castings, and to save fitting, theedges of the lateral sidesjof said flue castings are cut out, as shownat IILthus providing only three relatively short supports II for saidcastl ings at each side thereof.

Also, as said flue castingsb are installed for use, the areas-of theshell I of the kiln exposed in the spaces between adjacent series ofsaid flue' castings-and which otherwise would be exposed directly to theintense heat in the kiln, are lined, as shown at I2. Said lining, may beof the same general character as the lining 2 used for lining otherparts of the kiln, but may consist of any suitable or desired material.As shown, the linings I2 are of substantially the same thickness as thatof other parts of the kiln, the relation being such that the surfacesthereof exposed within the kiln will be positioned between the sides ofthe flues remote from the shell I of the kiln, and the adjacent sides ofthe openings 9, thus closing said openings and, also, to a large extent,protecting said castings from the excessive operating temperatures inthe kiln to which they would otherwise be exposed.

As shown, the'ue castings b are provided with holes or openings I3directed inwards towards the center of the kiln and, for reasonspresently explained, are surrounded by flanges or nozzles I4, andmounted on the exposed sides of saidI of the flue castings on which saidtuyre blocks are mounted, respectively, and formed at the lateral sidesof said tuyre blocks, are flanges I6, which embrace corresponding sidesof said flue castings, as clearly shown, see Figs. 11 and l2. As shown,see particularly Figs. 3 and 6, both the flue castings band the tuyreblocks b are secured to the shell of the kiln, by the bolts 'I whichextend through open ended holes or slots I8 in the iianges I5, and boltholes formed in bosses I9 on the ue castings b, and in the shell oi' thekiln, being inserted into engagement with said slots and holes fromwithin the kiln. Also, said bolts are held from turning while nuts arebeing threaded thereto, by webs 20 formed on the flanges I5, arranged toembrace the heads of said bolts, as shown, see Figs. 5, 6, 11 and l2.

As shown, also, the lengths of said tuyre blocks are so proportioned andthey are secured v to the ilue castings b in such relation that theAflanges I5 will extend over and close any spaces between the ends ofadjacent ue castings, thus preventing granular pieces of clinker fromfalling into said iiue castings through spaces between the ends of saidtuyre blocks, or the spaces between the ends of adjacent flue castingsmay be closed by metal plates, not shown. As shown, also, see Fig. 6,shoulders 2I formed at the remote ends of the extreme tuyre blocks b',by engagement with the ends of the corresponding flue castings, operateto dene the approximate positions of said' tuyre blocks and on a ratherlong radius and merge into the outer 4 of the shell of the kiln, andformed in said fo1.

lowing sides of said tuyre blocks are discharge openings 22, which, asshown, are directed against the rounded leading sides of adjacent reartuyre blocks. In the preferable construction shown, each tuyre block b'is provided with a plurality of discharge openings, which, as shown, areround but may beof any desired shape and size, or each tuyre block maybe provided with only a single relatively large discharge opening.

In operation,the tuyre blocks b' are exposed directly to the hightemperatures used in calcining or sintering the material in the kiln,which by expansion and contraction thereof, develops internal stressesin said tuyre blocks, which it is found, causes themand particularly thesides thereof exposed within the kiln-to crack and often to break,requiring that they be replaced while they are otherwise serviceable.`

I have found in practice that this tendency to crack and break, to avery large extent, can -be overcome by forming slots 22" in the sidesthereof exposed within the kiln, extending from the following edgesthereof towards their fleading edges, and which preferably are extendedin the following walls of said tuyre blocks so as to cut into 4thedischarge openings 22. In accordance with what I consider a preferablerelation for usual purposes, the slots 22' are about three inches (3")long, by one-quarter of an inch fwide, and terminate, at their closedends in substantially round holes 222.

As shown, also, the flanges or nozzles I4 which surround the airdischarge holes or openings I3 in the flue castings are higher at theirfollowing than at their leading sides.

With a recuperator B, comprising the elements described, and mounted inthe manner and relation specified, it is obvious, that, under usualoperating conditions, any tendency for granular material .to pass fromthe kiln into said recuperator will be negligible.'

In accordance with the present invention, air

under pressure is adapted to be supplied to the recuperator and coolerB, and discharged therefrom into' the kiln A, by means asfollowsz-Surrounding the shell l of the kiln in proximate relation tothe zone thereof te which the recuperator and cooler is applied, and inspaced relation to the shell of the kiln, is an annular wind-boxdesignated as a WholeC, which, as shown, is movably supported on xedframes or standards 23 erected l0 at opposite sides of the kiln, so asto be movable in4 both directions, axially of the shell l of the kiln.As shown, said wind-box is supported directly by wheels 24 rotatablymounted on opposite sidesl thereof--being, as shown, mounted on studs ortrunnions 25 secured thereto-and which are arranged to run on tracks 26supported on the frames or standards 23, the treads of which areinclined at substantially the same angle and in the same direction asthe axis of rotation of the shell of the kiln. 'For reasons presentlyapparent,

said wind-box'is maintained yieldingly at the limit of its movement inthe direction of the discharge end of the kiln, by means of weights 2lsuspended by cables 28 secured to opposite sides of said windbox andwhich run over sheaves 29 rotatably mounted on brackets 30 secured tothe frames or standards 23 and on said standards, as shown.

In operation, air under pressure is supplied to the wind-box C throughconnection of a anged 30 fitting 3l thereon with a source of air supply,not

shown, and from said Wind-box to the recuperator and cooler B, by meansas followsz--Supf ported in proximate, spaced relation to the zone ofthe shell I of the kiln A, in which said recuperator and cooler isinstalled, are manifolds 32, which are supported by and communicate withsaid recuperator. and cooler through nipples 33 opposite ends of whichare connected into holes formed respectively, in said manifolds and inthe shell i of said kiln, and which rigidly support said manifolds inxed position relative to the shell ofv the kiln, the relation being suchAthat said nipples will communicate directly with the flues 6 formed inthe recuperator and cooler by the flue castings I?,A

4;, and such also that nipples which communicate with the same manifoldswill communicate with the same fiues 6. As shown, each manifold 32 isconnected with theshell l of the kiln by two nipples 33, but thisrelation may be varied, as

5,0 desired, to meet requirements.

In accordance with what ll now consider preferable construction, saidmanifolds 32 and nipples 33 are made of suitable sheet metal, as sheetsteel,

the ends of said nipples connected to said manifolds being welded or,otherwise secured thereto, and their opposite ends being connected tothe v shell of the kiln by means of sheet metal collars or flanges' 3dsecured thereto, Asee Fig. 6, and which conform to the curvature of theshell l, preferably being welded to said nipples and, also, to the shellof the kiln. To save fitting, the ends of said nipples secured to theshell of the kiln are loosely fitted to holes formed in said shell,leakage of air around said nipples being prevented by the collars orflanges secured thereto.

The wind-box C is made of suitable sheet metal, is rectangular incross-section--its front and rear sides being flatl and subsantiallyparallel and positioned in planes, which, respectively, are substanmtially perpendicular to the axis of rotation of the Ashell of the kiln,and which, excepting for limited bodily movement thereof axially'of theshell of the kiln, is stationary.

'The interior of the Wind-box C is divided by a'. uv diaphragm orpartition 35, into compartments 36 and 3l, the air' supply fitting 3lcommunicating directly with the compartment 36, and the compartment 3lcommunicating with the manifolds 32 by means comprising nipples 38corresponding ends of which, respectively, are welded or other- 5 Wiserigidly secured in holes or openings formed in the proximate ends of themanifolds 32 with their ends projecting into said manifolds a shortdistancefsay for usual purposes, about two inches (2), thereby providinga trap which Will operate, 10 in an obvious manner, to prevent granularmaterial from passing from said manifolds into said nipples and thenceinto the wind-box C,

As shown, the means of communication between the Wind-boxC and themanifolds 32 also com- 15 prises a blast-ring 39, which is secured tothe nipples 38 and is provided with ports dll, 4each of which is in opencommunication with the bore of a nipple 38 and which are adapted to bebrought into communication with ports formed in the 20 wind-box, incontinuous succession during operation, by rotation of the kiln A. Y

In the preferable construction shown, the blast-ring 33 is secured tothe nipples 38 in such manner that it will have capacity for limited 25adjustment endwise thereof for adjusting the positions of the manifolds32 and blast-ring 39 relative to each other. To provide for suchadjustment, the nipples 33 have screw-threaded engagement with thejbores of tubular .fittings 3o di detachably secured to said blast-ringand arranged to be secured thereto in different angular adjustments. Asshown, the ttings il are secured to the blast-ring 33 by means of boltsinserted through holes formed inbase flanges 354 on said fittings, whichhave threaded engagement with corresponding holes in the blast-ring 39,all of said holes being arranged equal, angular distances apartsay sixtydegrees (60)-where by said bolts will` be interchangeable in said bolt40 holes, thus providing for securing said fittings to said blast-ringin different angular' positions,` and providing for limited adjustmentof the Wind-box C andthe manifolds 32 towards and from each other, tofacilitate installation of said 45 manifolds.

In accordance with the invention, see Figs. d and 6, leakage of air fromthe wind-box C past i the blast-ring 33, is prevented by means ofannular Wear-rings d2, d2', secured to the innerf and 50 outer marginaledges of said blast-ring, and which extend entirely around the same, oneinside and4 the other outside of the portsl or openings du, and withwhich the outer side of the rear wall d3 of the wind-box-Which forpurposes of conver- 5 ient' references may be designated theWearplate-isheld yieldingly in contact by the weights 2li, applied tosaid wind-box, which, necessarily, must be sufficiently heavy tocounteract the force of an unbalanced air pressure in the wind-box 60tending to force said Wind-box away from said blast-ring 3@ andthe-wearrings ft2, d2', thereon, which would operate, in an obviousmanner, to cause leakage of air between the rear wall or Wear plate i3of the wind-box and said blast-ring. 65

As shown, also, the ports or openings ll@ in the blast-ring 33, withwhich the open ends of different manifolds 32 communicate, as hereto--fore explained, are blocked-olf atbothV sides by suitable barriers fifi,arranged ta confine air pass- 7o ing from the wind-box to a manifold, toprevent it from passing laterally into the space defined by thewear-rings d2, d2' between the blast-ring 3@ and the proximate wall ofthe windbox,4and entering manifolds other than those which are 75 incommunication with the port or opening lrr the wind-box designed forsupplying air under pressure to said manifolds from said wind-box inusual operation, which would result in seriously impairing operation ofthe kiln, as it relates to pre-heating air intended for combustionpurposes and for cooling clinker discharged from the kiln. What I nowconsider preferable barriers for the purpose, consist of angle-bars madeof relatively soft metal, as brass, a flange of each of which is rivetedor otherwise secured to the blast-ring 39 and the other flanges ofwhich, respectively, extend substantially at right angles to the side ofsaid blast-ring to which said angle bars are secured, the initial heightof said projecting iianges being slightly greater than the thickness ofthe wear-rings 42, 42. Thus, as iirst installed, the outer edges of saidflanges will contact with the adjacent wall of the wind-box C and willprevent contact of the wear-rings with the rear wall or wear plate ofthe wind-box, but

will quickly be worn down to a height equal to the thickness of saidwear rings by rotation of the shell `of the kiln. As shown, also, saidanglebars 44 are installed with their opposite ends in contact with saidwear-rings 42, 42', respectively, so as to form tight joints therewith.l As shown, also, the angle-bars which thus block-off the ports in saidmanifolds. converge/outwards at angles of about degrees to each other,and symmetrically with reference to radial lines of said blastringthrough the centers of said ports respectively.

In accordance withthe invention, see Fig.'5, air under pressure admittedto the` chamber 36 4 of the wind-box C is delivered tothe manifolds 32through a port 46 formed" by registering openings in the diaphragm 35and in the rear Wall or wear plate of the wind-box, said port openingsbeing circular and their axes being coincident with the axis of rotationof the blast-ring 39 and positioned at the same radial distance from theaxis of rotation of said blast-ring as the tubular iittings 4i on theblast-ring 39. As shown, the port 46 is positioned substantiallysymmetrically, circumferentially of the shell l of the kiln, with theangle of repose of the body of clinker D therein, in operation, therelation being such that the tuyre blocks b' which are in communicationwith the port 46 at any given time, will be covered by the deep body ofclinker which over-lies the sector of said angle of repose. As shown,also, said port 46 is of such length that more than one manifold willcommunicate therewith at the same time, said port being made suicientlylarge to insure an adequate supply of air to themanifolds 32 to meetcontemplated operating requirements.

As shown, the space between the diaphragm 35 and the rear wall of thewind-box is closed,

' in register with opposite edges of the port openings therein,respectively, by angles 41, secured tothe diaphragm 35, and which arebent to conform to the curvature of the said port openings 46 and whichform substantially tight joints with said diaphragm and wind-box wall.

As shown, also, opposite ends of the space between said angles 41 areclosed by dampers. 48, which are slidably .fitted to said space withsuitable operating clearance, and are separately adjustable to providefor varying the operative length of the port openings 46 and to vary thecircumferential position thereof relative to the angle of repose of thebed of clinker D, within limits. In what I'now consider preferableconstruction, best shown in Figs. 19 to 22, inclusive, the'side and endplates of the wind-box are connected by corner angles 49 to which theyare riveted or otherwise iconnected so as to form tight joints, and thediaphragm 35 is connected to the rear wall of the wind-box by bolt andspacing sleeve construction, as will clearly be understood from thedrawings Without a description thereof in detail.

Also, in what I now consider preferable construction, the dampers 48 are'made of suitable sheet metal, are rectangular in shape and are adaptedto be secured in adjusted positions by means of nuts 50 threaded tostuds 5I secured in said dampers adjacent opposite lateral edgesthereof, which project through slots 52 formed in the diaphragm 35concentric with the axis of rotation of the blast-ring 38, as willreadily be understood, adjustment of the dampers 48 in both directions,and thus the length of the port 46, being limited by contact of thestuds 5I with the ends of the slots 52.

As shown, also, see Fig. 5, plates 53 are se-l `curvature of saiddampers and being secured thereto with their proximate ends flush withthe corresponding ends of the dampers to which they are secured,respectively, and being of such length that, when said dampers are intheir positions of nearest operating approach lto each other, the remoteends of said plates will cover and close any portions of the portopening 46 in the diaphragm 35 which may extend beyond the remote endsof said'dampers proper, respectively. Also, for convenience in adjustingsaid dampers, they are provided with handles 54 on their proximate ends,see Fig. 10, which project through the port opening 46 in the diaphragm`35 into the compartment 36 of the wind-box and will be convenientlyaccessible for 'manipulating said dampers to adjusting the same, byremoving the cover plates 55 of hand-holes formed in the front Wall ofthe wind-box, indicated in diagram in.

Fig. 7.

As shown, see particularly Fig. 5, the diaphragm 35 of the wind-box isprovided with ports 56, separate from the port 46, which connect thecompartments 36 and 31 of the windbox, and formed in the rear Wall orwear-plate 43 of the wind-box are ports 51, see Fig. 5 with which theports 40 in the blast-ring 39 are adapted to be brought intocommunication in contiuous succession, in operation. The ports 56 arecontrolled by hand valves 58. With the construction described, it isobvious that cool air may be supplied to the kiln through the tuyreblocks not covered by the body of clinker D in said kiln, to preventover-heating of said tuyre blocks.

As shown, there are three (3) ports r56 in the diaphragm, but the numberthereof may be varied, as may be desired.

In accordance with usual practice, the kiln comprises what is knowngenerally as a firing hood for closing its clinker discharge end.However, such ring hood forms no part of the present invention and noring hood is shown, though a hood suitable for the purpose can readilybe supplied by mechanics familiar with such structures.`

To prolong the life of the wear-rings 42, 42', and of the rear wall ofthe wind-box C, against which said wear rings bear, means are prefer- 75ably provided for lubricating the contacting faces thereof. What I nowconsider preferable means for the purpose, see Fig. 22, consists of atubular fitting or fittings 59 controlled by anoutwardly seating checkvalve or valves, not shown, and mounted on the Wind-box C with the frontend or ends thereof projecting 'at the front side of said wind-box, inposition for making grease gun connections thereto, and with theirdischarge end or ends opening through the rear Wall of the wind-box, andarranged to discharge grease between the contacting surfaces of saidrear wall andthe wear rings 42, 42 on the blast-ring 39.

Fittings suitable for the purpose may be purchased commercially and neednot, therefore, be shown or described in detail.

Inv accordance with usual practice, the kiln A comprises a nose-ring 60secured to the clinker discharge end o( the shell i of the kiln, saidnose-ring extending inwards beyond the inner surface of the preheaterand Jcooler B, as shown, in such relationias to increase the thicknessof the bed of` clinker in the kiln, as will be readily*lv ingconnections on the shell of the kilnv consociation with said kiln, meansfor supplying air under pressure to said wind-box, a diaphragmlwhichdivides the wind-box into compartments,

. said diaphragm and the rear-wall of the/Wind-box.

being provided with segmental blast-openings, means for closing thespace between said diaphragm and the rear-wall of the wind-box insubstantial register with the corresponding edges of saidblast-openings, and dempers which close the ends of said space, therelation being such that rotation of theshell of the kiln will bring theports in the blast-ring into communication withk the blast-openings ofthe wind-box in continuous succession during operation.

2. A kiln comprising arotaryshell, a lining therefor, including acombination recuperator and cooler for preheating air supplied to thekiln and cooling material discharged therefrom, means for supplying airunder pressure to said recuperator and cooler, comprising airdistributing connections on the shell of the kiln constructed andlarranged to'communicate with said recuperator and cooler, a blast-ringprovided with vports secured to the air admission ends of saidassociation .with said kiln, means for supplying j air under pressure tosaid wind-box, a diaphragm which divides the wind-box into compartments,

said diaphragm and the rear-wall oifthe wind-l v box being provided withsegmental blast-openf ings. means for closing the space between saiddiaphragm and the rear-wall of the windbox in substantial 'register'with the corresponding edges of said blast-openings and wear-ringssecured to the blast-ring at radially opposite sides of the portstherein, with which the rear wall of the wind-box contacts duringoperation.

3. A kiln comprising a rotary shell, al lining therefor, including acombination recuperator and cooler for preheating air supplied to thekiln and cooling material discharged therefrom,

l means for supplying air under pressure to said recuperator and cooler,comprising air distributing connections on,v1 the shell of the kilnconstruoted and arranged to communicate with said recuperator andcooler, a blast-ring provided with ports secured tothe air admissionends of said air distributing connections with the ports thereof incommunication with said air distributing connections, a wind-box mountedin association with4 said kiln, means' for supplying air under pressureto said Wind-box, a diaphragm which divides the Wind-box intocompartments, said diaphragm and the rear-Wall of the Windbox beingprovided with segmental blast-openings, means for closing the spacebetween said diaphragm and the rear-wall of the wind-box in substantialregister with the corresponding edges of said blast-openings, damperswhich close the endsof said space, Wear rings secured to the yblast-ringat radially opposite sides gf the ports therein, with which the rearwall of the windbox contacts during operation, and barriers on theblast-ring which extend between the proximate edges of the wear-ringssecured thereto and block oif the ports therein at both sides thereof.

4. A kiln comprising a rotary shell, a lining therefor, including acombination recuperator and cooler for pre-heating air supplied to thekiln and cooling material discharged therefrom, said recuperator andcooler consisting of trough-v shaped members secured to the shell of thekiln with the edges of their .open sides in contact therewith,andarranged to form a series of iiuesv spaced apart circumferentially ofthe kiln, nozzles formedl on said flues, tuyre blocks supported on saidues. whichj extend over said'nozzles, respectively, and means forsecuring said flue members and tuyre blocks to the lshell of the kiln,

comprising inwardly projecting end iianges arranged to rest on the sidesof 1said ilues remote from the shell of the kiln, provided with slots,and bolts which extend through said slots and through holes formed insaid flue members and in the shell of the kiln, and means for closingthe ends of said flues. f

5.' `A kiln comprising a rotary shell, a liningl therefor, including acombination recuperator and cooler for preheating air supplied' to thekiln and cooling material discharged therefrom, means for supplying airunder pressure to said recuperator and cooler, comprising airdistributing connections on the shell of the kiln constructed andarranged to communicate with said recuperatorand cooler, a blast-ringprovided with ports, secured tothe airv distributing connections on theshell of the kiln with said ports in communication with saiddistributing connections,

respectively, said ports beingarranged in a circular seriessubstantially concentric with the shell of the kiln, a diaphragm whichdivides said wind-box into compartments,l said diaphragm and the rearwall of the wind box being provided-

